The invention relates to a substrate support for holding substrates or wafers to be processed and for transporting them in or through process plants.
Substrate supports, which are also referred to as carriers or boats or plasma boats, are used in the semiconductor or photovoltaic industry for transporting substrates or wafers composed of glass, silicon or other materials in or through process plants. Such substrate supports or carriers are necessary in particular if the substrates or wafers are particularly sensitive or particularly thin with a large surface area, such that direct transport thereof, that is to say without using auxiliary means, is not possible because of the risk of damage.
The substrate supports or carriers are usually made of plates provided with additional means for holding, attaching or placing the substrates or wafers.
For example, WO 02/20871 A1 discloses a wafer support/carrier, which is made of a plate having a plurality of mutually adjacent cutouts each for horizontally holding one substrate, the cutouts having only slightly larger dimensions than the substrates. Inside the cutouts are three placement pins, on which the substrates are to be placed. Owing to this three-point placement, the maximum possible electrical contact stability is achieved, as is necessary for plasma processes, e.g. PECVD processes. The plates themselves are composed of graphite, owing to the temperature stability and the necessary electrical conductivity.
The in this case square substrates are fixed in the plane by at least partially dipping into the cutout and are thus fixed in the x and y directions. The cutouts are milled into a solid plate and permit automatic placement of the substrates or wafers.
However, the manufacture of such solid plasma boats is relatively complex due to the mechanical processing required.
A similar construction is disclosed in WO 02/056338 A2. Here, too, a substrate support with depressions, which have been incorporated with as accurate a fit as possible, is used for transporting the horizontally arranged substrates, which substrate support likewise has quite a high mass. The substrate support including the substrates positioned thereon is transported on rolls through a mass tunnel of a process plant, in which mass tunnel HF/VHF electrodes are arranged.
Other materials can of course also be used for the substrate supports, such as CFC/CFRP (carbon-fiber reinforced plastic) or a CF/ceramic matrix, that is to say a high temperature matrix, or else metal.
The use of whole crude plates results in a significant usage of materials and processing outlay and also a relatively large amount of waste. In addition, solid substrate supports are useable with little flexibility, i.e. the substrate supports are useable mostly only for a specific process. This means that a multiplicity of substrate supports must be stocked.
For this reason, substrate supports which are useable as universally as possible or are easily adaptable for concrete tasks would be desirable.